In my experience you can get this working by holding the delete/backspace down for half a second, if hold down longer than that though it starts spamming qustion marks for me whish is… Weird.
There is a weird graphic glitch with the portal clipping through blocks when they are placed on the other side of the portal:
(As seen above the wood block you are actually watching the landscape through a stone block on the other side of the portal:)
